Month: October 2019

I am not very adept at soldering, so in general I don’t do repairs of electronics at the board level. But the idea of having to pay Apple quite a bit of money to replace an ailing battery just rubbed me the wrong way. I had an iPhone 6 plus. The battery was not holding a charge very long. This particular phone was actually part of the giant “we’ll replace it for USD $29” scandal, so it wouldn’t have set me back that much, but since I was considering getting a new phone anyway, I decided to try to replace the battery on my own just to see if I could get comfortable doing such a thing.

The first “go to” place on do-it-yourself gadget repair is ifixit. They have all kinds of guides, and will sell kits as well. I basically followed their guide to replace the battery in my iPhone 6 plus, and old iPhone 4, and an iPad mini 2. Each of the guides are reasonably good, but here is what I would do differently, or what I now feel is common sense.

1. You can probably get the replacement batteries on Amazon or Aliexpress. The quality of all these batteries is all questionable in my mind. I at least try and find ones with the PSE mark (which of course could also be fake). I look at comments and try and see if most are fake comments or real. Also, it seems these batteries have a warehouse shelf life. Some companies will advertise a “less than six months old” policy that may be worth it. (I had one iPhone 4 battery that was DOA.)
2. Don’t do this when you are in a hurry. They have a reference time on some of the guides. Just assume you are going to need a couple of hours.
3. Take the time to cover your work area with light-colored paper or a plain table cloth. You will almost always lose a screw or other little part, and usually you will want to find it.
4. Print out the guide unless you have an extra tablet to view. Mobile phone screens are too hard to focus on when you are back and forth with your work.
5. I like to print out a photo (your own or from ifixit) on A4 (or Letter-size) paper and then put double stick tape next to each screw in the photo. Then, when I take out a screw, I set it on the double stick take next to its own photo, and that helps me get the right parts back in later.
6. You can make the heating pad that is shown on ifixit out of socks and rice. I found that men’s socks are too big as socks will stretch quite a bit as they are filled with rice. Also, sewing through (like a quilt) in a few places helps keep the rice a bit more evenly distributed. When you heat this in the microwave, a fair amount of moisture will come out. Use common sense when putting it on the device. I found that setting the device in front of my kerosene fan heater got things pretty warm, and then I put the socks/rice heating pad on that for the final touches.
7. I would suggest you buy a new set of screws for the device before you start. Aliexpress has these for very little money–just get a set.
8. Ditto with the “seal sets”. Aliexpress will have them. These are some sort of seal adhesive that is set in the same shape as the screen. When you remove the screen, you essentially heat this stuff up so that the screen will come off. The seal is typically somewhat damaged in the process. The phone will still go back together just fine, but my guess is the water-resistance is significantly decreased.

If you assign a value to your time, then I would say it is NOT worth it to replace iDevice batteries yourself. However, if you look at the time you spend fixing it as recreation, then you can save a significant amount of money doing it yourself.

As my incandescent light bulbs burn out, I have been replacing them all with LED bulbs and the house has pretty much been converted. (Some I have been a bit more proactive.) The monetary benefits of moving from incandescent to LED is pretty clear. However, fluorescent lights are already pretty energy-efficient, so I haven’t really been motivated to change them. However, this changed with the long fluorescent tube in the kitchen started flaking out. At first I put in a new tube. Unfortunately there was no change-still flaky. That meant the quick starter or the ballast must be on the blink, so my choices were between getting parts for the light fixture, or replacing the entire fixture. Parts replacement in Japan can be a real pain, as there are not many third-party manufacturers and trying to figure out something compatible can be tricky. A new fixture is quicker at about $100, but from my experience parts are going to come close to that anyway. So, I started looking at LED lighting, and found that those lamps don’t like starters and ballasts, but like to be wired direct. Hmmm. I ordered just an LED tube replacement at $28, took the ballast and quick starter out of the circuit and wired it direct, and viola, everything working fine–pure satisfaction. Sure it took me half a day to come to this conclusion and then do the wiring. It’s a guy thing.

There are actually two types of Flourescent fixtures. I have created a schematic of sorts to illustrate the before and after wiring of each.

Disclaimer: This is offered for information-purposes only from a hobbyist, not an accredited professional. There is always the possibility that something I have stated is incorrect, so if you act on this, do so at your own risk.

Ballast + Starter arrangement:

Ballast only arrangement:

In either case, it is simply a matter of cutting the appropriate wires, stripping off the insulation on the ends, and then putting the appropriate wires together again. I used twist-on connectors for connecting the wires together again.

As I mentioned in my earlier post, much of the directions for how to do this came from the following site, to which I am truly grateful.

https://speakerrepairshop.nl/index.php/en/instructions/replace-tweeter-diaphragm/b-w-cdm-1-tweeter-zz09989-zz9989/c-42

Now, I also found schematics for the CDM1 on a site called “Elektrotanya”. Now, I am not so sure this site is entirely legit, so I won’t link to it directly, but I am sure you can search for it and find it. To be honest though, you don’t really need the schematics for what I did. Removal of the tweeter from the cabinet is really quite easy.

1. First, remove the speaker grills. The one covering the woofer just comes off by prying gently at the sides. The one covering the tweeter is a bit harder. Get as many fingers around it from both hands as you can, and pull slowly outward, maybe rocking slightly as you pull. The grill is attached to a plastic ring that sits in a groove, and the ring/grill should come off together.
   

2. Remove the tweeter assembly. The tweeter assembly is fastened to the speaker cabinet with three screws. One is on top. Be sure you have a Phillip’s screw driver ( + driver) with the right size head to avoid shaving off the screw head.

To get at the two screws at the bottom of the tweeter assembly, carefully lift the rubber woofer flange to fully expose the screw heads. It may be a bit brittle, so don’t move it any more than necessary or you risk it falling apart.

3. Unhook the speaker wires. The wires have terminals that will just slide off the speaker lead plate. The OEM tweeter already has one lead marked with RED color, so you are probably OK, but this might be a good time to snap a photo so you can remember which is which. Also, taping the wires to the cabinet with electrical tape before you let them go can save you from having to hunt in the inside of the cabinet for them later.

4. Remove the driver from the plastic housing. The tweeter is held in place in the plastic housing by a metal bracket. You just need to remove the two screws and set the bracket aside. Note that under the part number label, there is a felt pad that is meant for the metal bracket to push against to dampen any vibrations. Leave this intact.

The driver is just sitting in the plastic housing. You can remove it by pulling on the plastic that houses the leads.

Once the tweeter is removed from the housing, it is probably a good time to wash the housing to give it time to dry while you are doing the other work on the tweeter itself.

5. Disassemble the tweeter driver. The magnet and the dome/voice coil assembly are held together with glue. Holding the magnet firmly in one hand, use your fingernails and slowly pry the dome assembly away. Try to move around the circle so that it separate evenly to avoid damaging the voice coil.

It is probably best to check the dome/voice coil assembly for any noticeable damage. If you see any, you will probably need to replace the tweeter entirely.

6. Clean the dome/voice coil assembly. You will need to clean off the old glue that is around the outside ring. Be very careful not to break the very thin voice coil wires while doing so. I found that using alcohol and a wooden toothpick followed by a cotton swab did the trick.

You will also need to clean off the dried ferrofluid from both the voice coil and the inside edge of the dome. I used alcohol and a cotton swab for this. One thing to watch on the inside is there is a joint that the cotton fibers can get stuck in, so be especially careful there.

7. For cleaning the ferrofluid left in the magnet, I first tried the “insert paper” method. That got some out. What worked the best for me was to pour some alcohol in the crevice between the magnets, and then use a plastic toothpick and go all all the way around, bringing up particles as I went along.

Many of the particles that were originally in the ferrofluid will stick to the magnets. About the only way to get them out is to use tape. I used some slightly thick double stick tape with the waxy paper still intact on one side. That allowed me to slip the tape between the magnets, then once inside I could push the tape against one wall, and slide it around to pick up particles. I repeated this for both the inside and outside walls until the tape was more or less clean.

8. Replace the ferrofluid. Once you have cleaned everything and allowed time for any alcohol to dry, it is time to replace the ferrofluid in the magnet. This stuff may be a bit difficult to find. I live in Japan, and so procured mine from an eCommerce company called Baysidenet.

http://www.baysidenet.jp/c-item-detail?ic=0844632086328

I found what looks like the same stuff on Amazon.

https://www.amazon.com/Ferrofluid-900uL-General-Purpose-Diameter/dp/B00HX0L2XO/ref=sr_1_1?keywords=speaker+ferrofluid&qid=1571733050&sr=8-1

It takes a very small amount of ferrofluid to fill the gap between the magnets. Both times I did this, I filled the entire cavity. It seemed prudent to then insert some paper and suck up some of the fluid, as when the dome/voice coil assembly is reinserted into the cavity, it will likely overflow.

9. Reassemble in the opposite way that you took everything apart. I did not worry about gluing the dome/voice coil assembly onto the magnet. I just squeezed the pieces together. These are held in place well by the metal bracket that pushes against the felt on the back of the magnet. As far as I could tell, I had no leaks.

10. Listen and enjoy! My tweeters both worked properly after doing this. As one might imagine, there was a huge difference once the tweeters were working again.

Remarks: I have seen other posts that said they did NOT replace the ferrofluid, and everything sounded just fine. I do not dispute this. While the one property of the ferrofluid is supposedly to be a coolant, I kind of doubt whether it is 100% necessary for average use. The ferrofluid is also supposed to dampen the sound somewhat. Those who prefer a brighter sound may prefer the tweeters without the ferrofluid. Personally I liked the original sound, so wanted to stick as close as I could to the original state.

I have a set of Bowers & Wilkins CDM1 speakers that I bought maybe 20 years ago. I bought them for the sound they produced first, but also I really liked the way the looked. After years of listening to them, one day I realized they just didn’t sound very good. At the time I did internet queries like “do speakers age?”, but they didn’t immediately lead me to suspect a particular cause. So, by this time I had a bit more money, and was thinking of slightly larger speakers anyway, so bought some DM602 S3 speakers to replace the CDM1. The DM602 S3 speakers sounded much better than my ailing CDM1 speakers, so that was that. I put the CDM1 speakers in storage thinking that someday I might just replace the drivers because I liked the cabinets so much.

Well, a few weeks ago I happened to come upon a post that talked about how many speakers around the era the CDM1 speakers were made used ferrofluid as a coolant and dampener for their tweeters, and that ferrofluid can dry out, causing a sludge that will lock the voice coil to the fixed magnet, meaning that it can’t move, which means no sound.

I pulled my CDM1 speakers out of storage, and tested them. Sure enough, I wasn’t hearing any sound out of the tweeters, so I did some further research specifically on CDM1 tweeters. The first thing I found was that you can’t buy new CDM1 tweeters from B&W anymore. (This was probably OK, because I don’t think I could have spent the kind of money they would have probably asked when I wasn’t 100% sure that the solution would work.) The second thing I found was that there were really three options I could take.

Option 1: Assuming my current tweeters had no damage (voice coil not burnt out, cloth/rubber diaphragm around the metal dome still working, etc.), it is possible that I could clean out all the old ferrofluid, and just replace it with new ferrofluid. (To be honest, not replacing the fluid at all is also an option it seems.)

Option 2: Assuming my current tweeters had damage to the diaphragm and/or voice coil, it is possible to clean out the old ferrofluid, replace it, and also replace the diaphragm/voice coil with an aftermarket one. The instructions for doing this I found on the following site.

https://speakerrepairshop.nl/index.php/en/instructions/replace-tweeter-diaphragm/b-w-cdm-1-tweeter-zz09989-zz9989/c-42

Now, the instructions for dealing with the ferrofluid were truly helpful to me (I did Option 1). Unfortunately, this site also said that the aftermarket diaphragm/voice coils were out of stock, so I wasn’t sure that this would be a realistic option as I couldn’t seem to find replacements anywhere.

Option 3: Replace the tweeters entirely with one that would fit well in the available space. I almost went down this path, but decided to try Option 1 first, and only replace the tweeters if the repair got too involved for me to continue comfortably. Now, had I chosen this option, the tweeters that I understood would fit in this space were the Tymphany OC25SC65-04 which are available at Parts Express in the US (seem to have worldwide shipping) or in Japan at Yokohama Bayside Net.

https://www.parts-express.com/peerless-by-tymphany-oc25sc65-04-1-textile-dome-tweeter–264-1018

http://www.baysidenet.jp/c-item-detail?ic=TPSP1953

Now, my understanding is that a bit of work still has to be done on the new tweeters as the posts are not in the same place as the original tweeters, but the size is apparently just right. Honestly I wondered if it would be possible to take the diaphragm/voice coil assembly out of these tweeters and have them fit into the original B&W driver magnets, but you would have to be fairly gutsy to do try this as the diameter of the voice coil may not be the same. (If anyone has done this, please let me know!)

Anyway, after considering my options, and with fingers crossed that my tweeters weren’t already fried, and that I wouldn’t damage them in the process of getting them cleaned up, I embarked on Option 1 above.
Replacing ferrofluid in B&W CDM1 tweeters